Apply correct typing to return values of black box functions

[kevaundray]

Problem

Functions like merkle_check_membership will return a Field whereas we ideally want it to return a bool

Solution

• The easiest solution would be to wrap the function in another function which does the correct typing using as.
• Another solution is to change the types of those functions to be bool for example and then enforce that they are in the compiler

Alternatives considered

Additional context

[TomAFrench]

Weren't we planning on avoiding passing in a root all together? (noir-lang/acvm#66)

[kevaundray]

Weren't we planning on avoiding passing in a root all together? (noir-lang/acvm#66)

Yep you are correct; issue may have not been clear -- This is for all blackbox functions that we have implemented in Noir that should return booleans, but we've typed them as Field. So this would apply for signature verification functions too.